Last month I wrote about how Major League Baseball is coping with climate change. As I reported, MLB is not only helping its players and fans adapt to extreme heat and humidity, many teams are doing their part by curbing their carbon emissions as part of a larger campaign to "green" baseball.

A new report by the Natural Resources Defense Council (NRDC) documents that pro baseball is not alone. The National Basketball Association (NBA), National Football League (NFL), National Hockey League (NHL), U.S. Tennis Association and Major League Soccer have all initiated efforts to go green. These measures range from reducing electricity, gas, water and paper use to installing solar panels to composting food refuse to recycling paper and plastic.

"Game Changer: How the Sports Industry is Saving the Environment," which NRDC released this week, provides numerous examples of how leagues are showcasing their sustainability programs during all-star games, championships and other high-profile events as well as how teams have upgraded their facilities to make them more environmentally friendly or built new, state-of-the-art, LEED-certified ones. According to the report, these efforts have saved millions of gallons of water; recycled or eliminated the use of millions of pounds of paper products; and, over the last five years, avoided some 20 million of pounds of carbon emissions, equivalent to the annual output of five average-size coal power plants.

Why is this a big deal?

The U.S. sports industry is huge, generating more than $400 billion annually in economic activity, and that has a significant ripple effect not only economically, but also culturally. As the NRDC report explains, "[P]erhaps no other industry is better suited to confirm that environmental stewardship has become a mainstream, nonpartisan issue. Hundreds of millions of people of all political, social, religious and economic backgrounds watch sporting events each year, and the global supply chain of the sports industry includes the largest and most influential corporations in the world. In fact, while only 13 percent of Americans say they follow science, 61 percent identify themselves as sports fans."

"What's driving this is twofold," NBA spokeswoman Kathleen Behrens told reporters during NRDC's telephone press briefing on Wednesday. "We see this as a matter of social responsibility and good business."

Social responsibility, no doubt. And it is definitely good business. The case studies in NRDC's report show that teams that do good also do well. The current NBA champs, the Miami Heat, for example, upgraded its arena in 2009, earning LEED certification for modifying an existing building. The renovations, which included energy and water conservation intitiatives, cost the team about $73,000. Since then, those improvements have saved the team more than $1.6 million a year.

Besides launching initiatives to cut energy, water and paper use, some leagues and teams have taken steps to educate fans about how they can reduce their environmental impact. For example, NBA teams host "Green Week" community service events that include tree plantings, recycling drives and park clean-up days, as well as "Go Green Awareness Nights" at their arenas that provide "greener living" tips. But more often than not the efforts described in the NRDC report focus on recycling, and there is a lot more that fans can do besides tossing empty bottles into a stadium recycling bin.

Then there's the fact that most fans don't attend games in person--they watch them on television. Last season, 17.1 million fans attended NFL games, but the regular season drew more than 200 million viewers and the Super Bowl attracted more than 111 million. Likewise, 342,878 fans attended last year's World Series, but more than 115 million Americans watched it on TV. How do you reach them?

Major League Baseball, the NBA and the NHL have produced public service announcements for television that tout what they are doing to be more environmentally friendly. But besides the fact that the PSAs don't air that often, they don't explain what fans can do on their own.

As it turns out, fans can do as good and as well as their favorite teams--they just need the information. A good place to start is a new book by the Union of Concerned Scientists (UCS) titled Cooler Smarter: Practical Steps for Low-Carbon Living. It spells out just how sports fans--and everyone else for that matter--can significantly reduce their carbon emissions and save money by, among other things, heating their homes more efficiently, buying more energy-efficient appliances and lights, and modifying their diets--along with driving a fuel-efficient car.

Here are some the book's top recommendations:

Keep your cool: You and your buddies want to be comfortable when you're jumping up and down after your team scores. UCS found that getting a professional energy audit to find and seal energy leaks can help reduce typical home heating and cooling loss by 15 to 25 percent. Besides weatherizing a home, installing a programmable thermostat--which can control the temperature when you and your family are asleep or away--is one of the least expensive and most-cost effective ways to lower carbon emissions and save as much as 15 percent a year on heating and cooling bills. Finally, you should consider replacing your furnace or boiler if it is more than 20 years old, has a continuously burning pilot light instead of electronic ignition, or isn't doing a good job heating your home--or if your heating bills are especially high.

Use less juice: Refrigerators are one of the biggest home electricity hogs, and new refrigerators use 70 percent less energy than those manufactured in the mid-1970s. Lighting can eat a lot of energy, too. Switching to energy efficient bulbs can cut annual lighting bills by at least 75 percent, which would amount to a $140 annual savings for a typical household. Also keep in mind that the television you're watching on game day also can run up your electric bill. If you are on the market for a new set, LCD sets with LED backlighting use less power than LCD sets with fluorescent backlighting or plasma models. Finally, your TV is likely never really "off." Some models consume more electricity in 20 hours off as they do when they are on for 4 hours. To really turn it off, plug it into a power strip and turn off the strip.

Cut the meat: Hot dogs and hamburgers are traditional game day fare, but the most effective thing you can do to curb the carbon emissions resulting from your diet is eat less meat, especially beef. That doesn't mean you have to go vegetarian. Just eating smaller meat portions, or skipping it occasionally, would make a big difference. The average American eats about 270 pounds of meat a year, which is nearly four times the global average. If a typical American family of four cut its meat intake in half, it could reduce its carbon emissions by about 3 tons a year.

There are a lot more helpful tips in the book, but these should give you a good idea that we all can do something to protect the planet and our pocketbooks at the same time. And by taking this opportunity to plug UCS's book, I don't want to take away from the welcome news that professional sports teams are stepping up to the plate for the environment. But they could do a better job informing their fans that they, too, can play this game. Going green shouldn't be a spectator sport.

Elliott Negin is the director of news & commentary at the Union of Concerned Scientists. He worked for the Natural Resources Defense Council from 1999 to 2006 and led the organization's campaign to make the new Washington Nationals ballpark the first LEED-certified sports stadium in the country.